Aetiology of malocclusion 2 Flashcards by Roisin Mousa

What is the etiology of malocclusion split into

skeletal
dental
soft tissue
other

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What are examples of skeletal issues that cause malocclusion

class III 
high FMPA

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What are examples of dental issues that cause malocclusions

missing teeth

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What are examples if soft tissue issues that cause malocclusions

lip trap

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What is the definition of local causes of malocclusion

localized problem or abnormality within either arch, usually confined to one, two or several teeth producing a malocclusion

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What 5 areas can local causes of malocclusion be divided into

variation in tooth NUMBER
variation in tooth size or FORM 
abnormalities of tooth POSITION
local abnormalities of SOFT TISSUES
local PATHOLOGY

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What are variations in tooth number

supernumerary teeth

hypodontia

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What is a supernumerary tooth

tooth or tooth like entity which is additional to normal series

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Where are supernumerary teeth most common

anterior maxilla

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Which gender are supernumerary teeth most common

males

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What is the prevalence of supernumerary teeth

1% in primary dentition

2% in permanent

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What are the four types of supernumerary teeth

conical
tuberculate
supplemental
odontome

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What is the shape of conical supernumerary teeth

small peg shaped
may erupt so extract
usually 1 or 2
tend not to prevent eruption but may displace adjacent teeth

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What are mesiodens conical supernumerary

mesiodens

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What are the tuberculate supernumerary

tend not to erupt
paired
barrel shaped
usually extracted

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What are the tuberculate supernumerary teeth

failure of eruption of permanent upper incisors

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What are supplemental supernumerary teeth

extra teeth of normal morphology
most often upper laterals or lower incisors
can eat raid premolars or fourth molars
often extract - decision based on form and position

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What are odontome supernumerary teeth

command - discreet denticles

complex - disorganized mass of dentine, pulp and enamel

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What is hypotonia

developmental absence of one or more teeth

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Which gender is hypodontia more prevalent with

females

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What teeth are most commonly effected by hypodontia

upper lateral 2s

second premolars

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What are retained primary teeth

a disruption in the sequence of eruption

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When should alarm bells ring about retained primary teeth

difference of more than 6 months between the shedding of contra lateral teeth (alarm bells)

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Why may primary teeth be retained

absent successor
ectopic successor or dilacerated
infra occluded (ankylosed) primary molars
dentally delayed in terms of development
pathology/supernumary

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What should you do if there is a retained primary tooth with an absent successor

either maintain primary tooth for as long as possible if it has a good prognosis or extract deciduous tooth early to encourage spontaneous space closure in crowded cases early ortho referral for advice is best

What are infra occluded primary molars

(was called submerging before) process where a tooth fails to achieve or maintain its occlusal relationship with adjacent teeth temporary ankylosis common in 1-9%

What type of sound do the infra occluded primary molars make

percussion sound

What is the management of a retained infra occluded primary molar if there is a permanent successor present

usually self corrects so keep under review consider extraction if 1. contact points are going subgingival 2. root formation of successor is near completion

What is the management of a retained infra occluded primary molar if there is not a permanent successor present

depends on potential crowding retain if in good condition extract and plan space management

What is early loss of primary teeth due to

trauma periapical pathology caries resorption by successor

What can early loss of primary teeth result in

crowding | centre line shift

What does the result of early loss of primary teeth depend on

which tooth is extracted when the tooth is extracted patients inherent crowding

What is a balancing extraction

extraction of a tooth from the opposite side of the same arch designed to minimize midline shift

What is a compensating extraction

by extraction of a tooth from the opposing arch of the same side designed to minimize maintain occlusal relationships

What is the impact of the early loss of primary incisors

very little impact | no compensating or balancing extraction needed

What is the impact of early loss of primary canines

unilateral loss in crowded arch, can give centre-line shift will et some mesial drift of buccal segments consider balancing extraction

What is the impact of early loss of primary molars

more space loss with Es and Ds more space loss in upper > lower 6's drift medially and steal 5s spaces tend not to balance or compensate

What is the effect when primary teeth are extracted

most effect is when primary teeth are extracted early | little effect is extracted late

What is the effect when there is inherent crowding

marked space loss in crowded px | minimal or no space loss in spaced dentition

When is the routine assessment for the prognosis of 6's done

at age 8-9 seldom ideal tooth of choice for relief of crowding but planned loss at correct age is better than later enforced loss

What are factors that influence the impact on the loss of 6s

age at loss crowding malocclusion

Is age an important factor for the age at loss for 6s

no | less important

When is the ideal time for extraction of 6's

ideally at time of bifurcation development in 7s

If the lower 6 is extracted too late what happens

the 7s have erupted already | often poor space closure

If the lower 6 is extracted too early what can happen

distal drift of 5s

If there is crowding in the upper arch and there is loss of 6s what can happen

rapid space loss

If the lower arch is spaced what is the impact on the loss of 6s

will have spaces

If the lower arch is aligned what is the impact of the loss of 6s

will have spaces

If the lower arch is crowded what is the impact of the loss of 6s

best results likely

If an upper 6 has to go do we compensate

If a lower 6 has to go do we compensate

often yes

What should we do about the unschedules loss of central incisor

in first instance maintain space by reimplanting | then plan how to deal with space

What are the 3 variations in tooth size and form

too large - macrodontia too small - microdontia abnormal form

What is macrodontia

tooth/teeth larger than average | localized or generalised

What are problems that arise from macrodontia

crowding asymmetry aesthetics

What is microdontia

tooth/teeth smaller than average localized or generalised leads to spacing linked to hypodontia

What are different abnormal forms of teeth

``` peg shaped laterals dens in dente geminated/fused teeth talon cusps dilaceration accessory cusps and ridges ```

What are abnormalities of tooth position called

ectopic teeth

What teeth are most commonly atopic

``` third molars upper canines first permanent molars upper centrals transpositions ```

What percentage of population have ectopic canines

1-3%

What percentage of ectopic canines are palatal

80%

What are ectopic canines associated with

small or absent upper laterals

How do we check for ectopic canines

check for palpable buccal canine bulge from 9 years onward | further investigation or refer if in doubt

What is the clinical assessment for ectopic canines

visualisation/palpation for any obvious bumps of 3 inclination of 2 mobility of c or 2 color of c or 2

How many radiographs are needed for ectopic canines

2 - usually OPT and anterior occlusal | can do vertical parallax too

What are the 3 Ps we look for in radiography of ectopic canines

presence position pathology

What are the management options for ectopic canines

prevention extraction to encourage improvement in position of 3 (interceptive) retain 3 and observe (accept its position) surgical exposure and orthodontic aligmnet surgical extraction autoimplantation

How can we prevent ectopic canines

appropriate to monitor from 9 onwards | clinical assessment - look for symmetry

How common are ectopic first molars

less than 5%

What arch are ectopic first molars most common in

upper

At what age are ectopic first molars reversible

What are signs of ectopic first molars

crowding | mesial path of eruption

What is management of ectopic first molars

seperator attempt distalize 6 extract e

When looking at ectopic upper central incisors what do we check for

sequence | symmetry

Why can upper central incisors become ectopic

supernumerary | dilacerated (trauma)

What is possible tx for ectopic central incisors

surgical exposure removal of supernumerary if present and bond a gold chain make space above 9 years ortho traction bonded retainers

What is transposition

interchange in the position of two teeth

What can transposition be classified into

true and pseudo

What teeth are most commonly transposition

upper canine and first premolar | lower canine and incisor

What are the tx options for transposition

accept extract correct

What are the 3 local abnormalities of soft tissue

digit sucking frenum tongue thrust

What is the effect of non nutritional digit sucking habits

proclined UI retroclined LI anterior open bite unilateral posterior cross bite

What can a labial frenum cause

median diastema

What can tongue thrust cause

anterior open bite

What are the local pathologies that can cause malocclusion

caries cysts tumours

Aetiology of malocclusion 2 Flashcards

(85 cards)